Treatment of footwear

ABSTRACT

Footwear is dried in a closed chamber by subjecting it to subatmospheric pressure to cause accelerated evaporation of moisture, solvents etc., therefrom. According to a different embodiment, water is sprayed onto the footwear whilst it is at sub-atmospheric pressure. Atmospheric pressure is then restored to drive the moisture into the footwear. Apparatus includes an open-ended chamber which is closable in pressure-tight fashion by pneumatically-operated doors. Shoe conveyor system extends through chamber to deliver to and remove footwear therefrom.

United States Patent Freedman 51 Aug. 8, 1972 [54] TREATMENT OF FOOTWEAROetjen et al. .34115 X 72 l t I 9 3,538,616 ..34/92 I 1 Road, gg 4Ormgbury 2,216,783 10/1940 Palmer ..34/15 x [22] Filed: April 1970Primary Examiner-Carroll B. Dority, Jr. [21] AWL NOJ 32,278Attorney-Larson, Taylor & Hinds [57] ABSTRACT [52] US. Cl. ..34/l, 34/9,Footwear is dried in a dosed hamber by subjecting it I 5 I] Int Cl 801k5/00 to sub-atmospheric pressure to cause accelerated evaporation ofmoisture, solvents etc. therefrom. [58] Fleld of Search ..34/l, 9,15,51, 92 cording to a different embodiment, water is Sprayed 56]Reterences cued onto the footwear whilst it is at sub-atmosphericpressure. Atmospheric pressure is then restored to drive UNI STATESPATENTS the moisteie iato t5: foolttvfiar. Asipargltus includes anopen-en c am r w 10 IS cosa e in pressure- 3,32|,842 5/1967 Boccrardo..34/l5 tight fashion y pneumaticallyflperated doors Shoe 2,373,3744/1945 Blerwlrth ..34/15 conveyor system extends through chamber todeliver to and remove footwear therefrom. 3:192:645 7/1965 Georg-Wilhem12 Claims, 6 Drawing Figures A x J QJUCICKJQ 6 PATENTEDAUB 8 m2 SHEET 1OF 6 DU UU 9 Kw N iilU 33F C i R4 C m PATENTED I 3 I973 PATENTED RUE 3I973 SHKU i BF 6 PATENTED 81973 3.681.850

SHEET SUF 6 PATENTEU M 3 I972 SHEET 5 OF 6 %\N**NNNH TREATMENT OFFOOTWEAR This invention is concerned with the treatment of articles offootwear during manufacture thereof. Where used in this specification,the term footwear" is in tended to include both complete articles offootwear and components thereof at any convenient stage of manufacture,preparation or after-treatment.

The treatment of footwear during manufacture includes the operations ofadding and subtracting water, stress relieving, the removal of solventsin the cement, pufi's, counters etc.

One conventional treatment method is heat setting". In this process, thearticles to be treated are mounted on lasts, and advanced through achamber in which they are subjected to the action of hot moist or hotdry air, for a period of, say 6 minutes. During this period the leatherbecomes tensioned over the lasts and each shoe upper assumes the shapeof the last on which it is mounted. An alternative treatment method isto leave the articles on the lasts for a period of 2 to 3 weeks. Theleather dries out during this time and is stress-relieved as it expandsand contracts with weather variations. Solvents used in adhesivesemployed during manufacture of the article evaporate during drying-outof the leather. At the end of the drying-out period, the articles arefound to have set in conformity with the shape of the lasts on whichthey are mounted.

Due to various factors such, for example, as efficient utilization offactory floor space, machinery, lasts and other equipment, it isdesirable that well-formed shoes be treated quickly. Manifestly, thelast-mentioned method does not fulfil this requirement. Heat setting onthe other hand is relatively rapid but has the disadvantage that it doesnot remove solvents and moisture trapped deep in the materials of theshoe.

An object of the invention is to provide an improved footwear treatmentmethod by which the footwear can be treated in minimum time. A furtheraim is to provide novel apparatus for performing this method.

Broadly considered, the method according to this invention comprises thestep of subjecting the footwear to sub-atmospheric pressure to causeaccelerated evaporation of liquid therefrom. It will be appreciated thatthe term liquid includes not only moisture but also cement solvents,e.g. acetone, etc.

The particular sub-atmospheric pressure to which the articles aresubjected depends on conditions. However, in practice, a pressure of theorder of 28 29 inches of mercury has been found to give satisfactoryresults. At this pressure, acetone and other solvents commonly used inadhesives in footwear manufacture also evaporate rapidly.

The period for which the footwear is subjected to sub-atmosphericpressure is preferably comparatively short, e.g. about 6 minutes. Thisenables the method of the invention to be performed on footwearassembled on a continuous-flow conveyor system and obviates theaforementioned 2 3 weeks drying out period during which, in the case oflast-mounted footwear, the lasts are out of use.

in addition, to pennitting efficient treatment of leather, it is foundthat the method of the invention is eminently suitable for the treatmentof synthetic materials used in footwear production e.g. Corfam(Registered Trade Mark).

The method of the invention relies on the well known fact that waterboils at C. at atmospheric pressure and at sea level, but atsub-atmospheric pressures will boil at much lower temperatures. It istherefore easier to extract water at sub-atmospheric pressures. This isalso true for solvents used in the construction of articles of footwear.

It is also well known that when a liquid evaporates. its temperaturedrops. Provision must therefore be made to maintain the articles at therequired temperature. To this end, the footwear may be either preheatedto an elevated temperature before being subjected to sub-atmosphericpressure, orheat may be imparted thereto while they are atsubatmospheric pressure.

In the former event, the footwear may be pre-heated by a heat settingprocess. In view of the fact that the temperature of the air used totreat the footwear during heat setting is usually of the order 100 C,subjection of footwear treated at this temperature to sub-atmosphericpressure causes extremely rapid evaporation of moisture from thefootwear.

Where heat is imparted to the articles of footwear whilst they are atsub-atmospheric pressure, radio frequency heating or induction heatingmay be employed.

It is also proposed, within the scope of the invention, to make thelasts on which the articles of footwear are mounted, at least partly ofa heat-conductive material, or to make the lasts of a plastics materialand incorporate therein, a conductive or semi-conductive material. Inthis event, the articles can be heated from inside by subjecting thelasts to radio frequency waves, thereby to raise the temperature of theheat conductive material.

To moisten (or hurnidify) articles of footwear, the preferred method isto remove air from the articles and replace it by a controlled mixtureof air and moisture. According to the invention this may be achieved bythe step of applying excess moisture to the footwear whilst maintainingthe same at sub-atmospheric pressure and then restoring atmosphericpressure.

It is found when using this method that moisture deposited on articlesof footwear whilst they are at subatmospheric pressure is drawn into theleather when atmospheric pressure is restored.

The invention also provides apparatus for performing the broad methoddefined above, this apparatus comprising a chamber which is scalable inpressuretight fashion; pressure-reducing means connected or connectableto the chamber; and means for transporting footwear into and from thechamber.

If desired, means may be provided for imparting heat to the articleswhilst they are being introduced into the chamber and/or whilst they areactually being treated in the latter as mentioned above.

Said pressure-reducing means will usually comprise a standard vacuumpump which may include water-extraction means.

The apparatus may be employed to moisten or humidify the footwear by theprovision of means for introducing moisture to the chamber at requiredtimes for deposition on the articles of footwear.

Preferably, the moisture is introduced into the chamber through one ormore spray nozzles arranged to spray water onto the articles at requiredtimes to humidify the same.

In order that the invention may be more clearly understood and readilycarried into practical effect, one specific embodiment thereof will nowbe described, by way of example, with reference to the accompanyingdrawings, wherein FIG. 1 is a diagrammatic plan view of a conveyorsystem incorporating footwear treatment apparatus in accordance with theinvention,

7 FIG. 2 is a detail plan view, partly in section, of the footweartreatment apparatus of FIG. 1,

FIG. 3 is a side view, partly in section, corresponding to FIG. 2,

FIG. 4 is a sectional view on line IV IV of FIG. 3,

FIG. 5 is a perspective view from one side of part of the apparatusshown in FIGS. 2 to 4, and

FIG. 6 is a side view, partly in section, of further apparatus forincorporation in the conveyor system of FIG. 1.

Referring to the drawings, the conveyor system will first be generallydescribed:

The system is, in fact, of the kind forming the subject of my priorU.K.betters Pat. No: 1,076,412 dated Aug. 13 1965. It comprises atrackway l for a plurality of wheeled work carriers 2. As can be mostclearly seen in FIG. 4, the trackway is in the form of a main channel 3,along the base of which run the wheels 4 of the carriers, and asub-channel 5 which depends from channel 3 and carries the driving meansfor the carriers 2. This driving means consists of an endless band 6 offlexible steel which has a continuous series of teeth 7 along its upperedge and is received in slotted nylon guide blocks 8 (FIG. 2) which arespaced at intervals along the base of sub-channel S and support the band6 in a vertical disposition with its teeth 7 projecting above the baseof the main channel 3 for engagement with catch means (to be described)on the underside of each of the carriers 2. The band 6 is adapted to bereciprocated to and fro in the slots in guide blocks 8 in use to drivethe carriers 2 (see below).

The trackway 1 is arranged in two parallel runs 9, the adjacent ends ofwhich are connected by curved runs 9a. At each of these runs 9a, thesub-channel 5 of the trackway 1 is cut away and the band 6 is secured tothe peripheries of the relevant one of two drums l0 and 11. Both drumsare turnable about vertical axes, drum 10 being freely tumable whilstdrum 11 is driven from a power unit 12. Unit 12 is constituted by anelectric motor in this embodiment, the output shaft 12a of which isvertically disposed and carries a radial arm 13. Shaft 14 on which drumI1 is mounted, also carries a radial arm 15, the ends of the two arms 13and 15 being connected by a link 16. Thus, the arrangement is such that,when motor 12 is in operation, shaft 120 and arm 13 are continuouslyrotated which causes arm 15 and hence also drum 11 to be oscillated.This causes a reciprocation of band 6 secured to drum 1 1.

Each of the carriers 2 in the system comprises a robust pressedsheet-metal body 17 having downtumed sides 18 which support axles 19 forthe front and rear wheels 4. Ajack pin 20 upstands from the body 17 ofeach carrier to receive a last L (see FIG. 4) on which are mountedarticles of footwear F. A loading hook 21 (see FIG. 4) is also providedon each carrier 2 to carry articles not mounted on a last, e.g. shoeuppers.

The above-mentioned catch device with which each carrier 2 is providedcomprises a metal strip 22 which runs along the central longitudinalaxis of the carrier at its underside and has a pair of depending sideflanges at its rear end which are mounted on the axle 19 of the rearwheels 4 of the carrier 2.

One end of strip 22 emerges from the front end of the carrier where itis turned upwardly. A short distance in from this end, strip 22 carriesthe catch proper. It comprises a plate 23 pivoted by its upper comers toa bracket 24 on the underside of strip 22, bracket 24 carrying a stop240. With the conveyor in use, the teeth 7 on the driving band 6 engageplate 23 when the band is moving in the intended direction of travel ofthe carriers, thereby bringing the plate into a vertical positionagainst stop 24a and driving the carrier 2 concerned. When however, theband 6 is withdrawn in the opposite direction, plate 23 turns about itspivots and the teeth 7 on the band 6 are drawn idly across its loweredge. Thus, the carriers 2 are intermittently driven by the band 6.

In the event that one carrier runs into or at least approaches the rearend of another carrier, the effect produced in the oncoming carrier isto pivot its catch strip 22 relatively to the axle 19 of its rear wheels4 and so lift the catch plate 23 out of the path of the driving teeth 7and bring that carrier to a halt.

As can be seen from FIG. 1, the carriers normally travel around thesystem in spaced positions past work stations SI and S2 at whichoperations are performed on the footwear F carried by the carriers.

At a selected location around the system, the trackway is interrupted toaccommodate a footweartreatrnent chamber generally designated C. Thus,the trackway terminates adjacent the front and rear ends of the chamber.The driving band 6 also terminates with the trackway, its free ends (oneadjacent each end of chamber C) being connected by a link 25 whichextends behind chamber C. This link will, of course, reciprocate withthe driving band 6.

It will be appreciated that each successive carrier 2 approaching thechamber C will come to rest where the driving band terminates, followingcarriers running into the rear of the stationary carrier and beingdisengaged from the drive strip as described above. The result of thisis to produce a batch B of stationary carriers in advance of chamber C.

Chamber C is of rectangular shape in cross-section with open ends. Apair of channel-section guides 26 are provided at each end of thechamber and extend one along the top and one along the bottom edge ofthe end concerned with their channels facing towards one another.Received in each pair of opposed channels is a sliding door 27 which isarranged to be opened and closed by a pneumatic cylinder and ram device28. The cylinder of this device is carried by a bracket 29, whichextends between channel member 26, and on a bracket 30 mounted on theside of the chamber C. The ram of the device extends through bracket 29and is secured to the door 27. A pair of wheels 31 which run in ballbearings are mounted on the door and run on the outer edge of the lowerchannel member 26 to ensure correct orientation of the door duringextension and retraction of the ram. A rubber sealing strip 32 isprovided to seal with the leading edge of the door when it is closed.

Chamber C is of robust steel construction so that, when the doors 27 areboth closed, it is pressure-tight and its walls are able to withstand aconsiderable reduction in internal pressure.

Three rectangular apertures are formed in the side of chamber C. Mountedon the wall of the chamber and arranged to normally close, two of theseapertures are a pair of pneumatically-operated valves 33, 34. Valve 33is connected to a vacuum pump 35 and water extractor 36 when in its opencondition. Valve 34 on the other hand is arranged, when open, to connectthe interior of the chamber to atmosphere. For the sake of convenience,details of the pneumatic piping to valves 33 and 34 has been omitted.

The third aperture is used to mount a water spray device (to bedescribed later) when required, being closed by a rectangular plate 37bolted to the wall of the chamber when not in use.

The equipment for introducing the batch B of carriers into chamber Cwill now be described.

Mounted on a support at the inner side of the trackway is a reversibleelectric motor 38 arranged with its drive shaft 39 horizontal. As can beseen in FIG. 3, this shaft carries a sprocket and drives, via a chain40, a larger sprocket 41 mounted on a further horizontal shaft 42. Shaft42 extends beneath the trackway 1 (FIG. 4) and receives a furthersprocket 43 at its outer end. This sprocket drives an endless chain 44around an idler sprocket 45, the arrangement being such that chain 44travels in two parallel runs, the upper of which extends beneath themain channel 3 of the trackway 1 at one side of sub-channel 5. Mountedon chain 44 by a pin which replaces the hinge pin between two adjacentlinks is a link 46 carried on the underside of a slide 47 which rests inthe bottom of the trackway. A slot 48 in the base of the trackway allowsthe slide 47 to move forwardly (i.e. in the direction of travel of thecarriers) at required times. Pivotally mounted in the recesses in theslide are a pair of catch members 49 each of which is spring-urgedupwardly for engagement with the front axles of the carriers 2. As canbe seen, one catch is arranged at the free end of slide 47 (i.e. the endnearest chamber C) whilst the other is, in FlG. 3, arranged to engagethe rearrnost carrier 2 in batch B.

In operation, the doors of chamber C open, whereupon motor 38 isoperated to move the slide 47 in the forward direction until it extendsright into chamber C; at this time link 46 has moved to a positionaround sprocket 45 which corresponds to the position in which it isshown on sprocket 43, in FIG. 3. Motor 38 then stops. The effect of thisis that the catch 49 at the front end of slide 47 engages the rearmostcarrier in chamber C and, by abutment with the remaining carriers in thechamber pushes the carriers from the chamber whereupon the ejectedcarriers are re-engaged by the driving band 6 and continue to be drivenaround the trackway. At the same time, the carriers in batch B are drawninto chamber C by the other catch 49 operating in similar fashion.

in operation, when the apparatus of the invention is to be used fordrying the articles of footwear F, a batch of carriers is inserted inthe chamber as described above and the doors are closed. Valve 33 isthen opened and valve 34 closed. By operating the vacuum pump 35,chamber C is evacuated to a pressure in the region of 22 to 28 inches ofmercury. A vacuum gauge 50 in the wall of the chamber indicates thepressure in the latter. This causes moisture, solvents, etc., in thearticle F to evaporate, these constituents being removed by extractor36. At the end of the treatment operation, valve 33 is closed and valve34 opened to reinstate atmospheric pressure in the chamber and allow thedoors to be opened for removal of the carriers therein.

The apparatus is preferably controlled automatically by means of asettable timer which determines the time for which the articles remainin chamber C, and by micro-switches arranged for contact by the variousmoving parts of the apparatus. Safety devices are also incorporated inthe control system, for example to prevent the doors 27 closing in theevent that a trolley accidentally comes to rest in the path of one ofthem.

To maintain the articles at a temperature above the evaporationtemperature of the moisture and solvents at the particular pressureprevalent in the chamber in use, means may be provided to impart heat tothe articles F whilst they are actually inside the latter. For thispurpose, radio frequency heating, or induction heating may be employed.In this event, the lasts L on which the articles F are mounted may bemade at least partly of a heat-conductive material, or of a plasticsmaterial in which a heat-conductive material is incorporated. Thearticles can then be heated from inside by subjecting the lasts to radiofrequency waves which raise the temperature of the heat-conductivematerial.

In one method of induction heating, lasts made of aluminum are employed.Electrical induction coils, represented schematically by heating coilsCHC of FIG. 5, are wound inside the chamber and are supplied, incontrolled fashion, with alternating electric current. This produces analternating magnetic field in the path of the lasts, which, in turn,generates eddy currents in the lasts, to heat the same. In this way,moisture is driven out of footwear on the lasts, from the inside.

As an alternative to, or in addition to this method, the articles F maybe pre-heated before entering chamber C. For this purpose, in accordancewith this embodiment, they pass through a heat-setting chamberimmediately prior to entering chamber C. This chamber is indicated at HCin FIG. 1 and is illustrated in more detail in FIG. 6. In thisembodiment, chamber HC is of the form disclosed in U.K.Patentapplication Ser. No: 42909/67 filed Sept. 21 1967 in the nameAutomagique (Conveyors) Limited; it will therefore be only brieflydescribed:

The chamber is open-ended having strip steel curtains 51 to inhibit heatloss from said ends. A partition divides the chamber horizontally belowtrackway 1. The lower part of the chamber includes heating coils 52, afan 53 and a water trough 54. The air in the chamber is blown by the fanand passes over the heating coils and trough S4, picking up water fromthe latter, and being delivered into the upper part of the chamberthrough outlets 55. Air inlets 56 enable a circulation of hot,moisture-laden air to be produced in the chamber.

With the above-described arrangement, the articles F are treated inchamber HC immediately before passing into chamber C at a temperature ofaround C.

As mentioned above, the apparatus shown in the drawings may also be usedfor moisturizing the articles of footwear F. In this event, the plate 37closing the third aperture (see above and FIG. in the chamber C isreplaced by a spray nozzle arranged to introduce a fine spray ofmoisture into the chamber. This nozzle may be a single or multi-jet typeand is connected to a spray device S indicated in chain lines in FIG. 5.

Device S comprises a pair of cylinders 57, 58 each of which receives apiston, the pistons being connected by a common piston rod 59. Cylinder57 is a hydraulic cylinder, whereas cylinder 58 is intended to receive asupply of water through a supply pipe 60. it will be noted that cylinder57 is of larger diameter than cylinder 58. This produces a pressuremagnification in cylinder 58, when the piston in cylinder 57 isoperated.

in use, water is drawn into cylinder 58 through supply line 60. Cylinder57 is then operated to force the water under high pressure from cylinder58, through the nozzle and into chamber C.

Where the apparatus is used for moisturizing the articles of footwear,the articles are first introduced into the chamber and the doors 27 areclosed. The pressure in the chamber is then reduced to around 22 to 28inches of mercury by pump 35. Whilst the chamber is still atsub-atmospheric pressure, moisture is sprayed on to the articles asdescribed above and atmospheric pressure is then restored by openingvalve 34. The effect of this is to draw the moisture into the materialof which the articles are made.

I claim:

1. Footwear treating apparatus comprising a conveyor system including atrackway; a plurality of carriers in said trackway; lasts on saidcarriers for carrying partly-finished shoes for treatment; drive meansfor intermittently driving the carriers around the trackway; a vacuumchamber through which the trackway passes; means for sealing saidchamber in a pressure-tight manner to enclose a group of last-mountedshoes for treatment; means for heating the shoes and lasts; andpressure-reducing means for subjecting the shoes within the chamber tosub-atmospheric pressure to cause accelerated evaporation of liquidtherefrom.

2. Apparatus according to claim 1 wherein said means for heating theshoes and lasts comprises induction heating means for heating the shoesand lasts while the shoes and lasts are at sub-atmospheric pressure.

3. Apparatus according to claim 1 wherein said heating means comprisespre-heating means for heating the shoes and lasts before entry into saidvacuum chamber.

4. A method of treating footwear comprising mounting partly-finishedshoes for treatment on lasts on carriers, conveying the carriersintermittently along a trackway and through a vacuum chamber, sealingsaid chamber to enclose a group of last-mounted partlyfinished shoes fortreatment, heating the shoes and lasts, and subjecting the shoes withinthe chamber to sub-atmospheric pressure to cause accelerated evaporationof liquid therefrom.

5. A method of treating footwear comprising mounting partly-finishedshoes for treatment on lasts on carriers, conveying the carriersintermittently along a trackway and through a vacuum chamber, heatingthe shoes and lasts prior to the entry thereof into said chamber,sealing said chamber to enclose a group of last-mounted partly-finishedshoes for treatment, and subjecting the shoes within the chamber tosub-atmospheric pressure to cause accelerated evaporation of the liquidtherefrom.

6. Apparatus according to claim 1, wherein the chamber is open-ended anddoors operable by pneumatic cylinder and ram devices are provided toclose the ends of the chamber in pressure-tight fashion at requiredtimes.

7. Apparatus according to claim 1, wherein the pressure reducing meanscomprise a vacuum pump including water extraction means, and wherein apneumatically-operated valve is mounted in the wall of the chamber toconnect the pump to the chamber at required times.

8. Apparatus according to claim 7, comprising a furtherpneumatically-operated valve mounted in the wall of the chamber andarranged to connect the interior of the latter to atmosphere at requiredtimes.

9. Apparatus according to claim 1, further comprising a water spraydevice connected to the chamber and arranged to spray water ontoarticles of footwear therein at required times, this device comprising apiston and cylinder unit arranged to be supplied with water; a spraynozzle in the wall of the chamber to which the cylinder of said unit isconnected; and a pneumatically-operated piston and cylinder unit oflarger diameter than said water cylinder, wherein the pistons of the twounits are connected so that movement of the pneumatic piston in onedirection causes water to be drawn into the water cylinder, and movementin the other direction causes the water in said cylinder to be deliveredto the spray nozzle.

10. Apparatus according to claim 1, wherein the carrier drive meansinclude a reciprocating saw-tooth drive band in the trackway, andwherein each carrier has a pivoted catch device on its underside forengagement by said band, the arrangement being such that the teeth onthe drive band engage the catch devices in one direction of bandreciprocation and drive the carriers, but pass idly across said devicesin the other direction of strip reciprocation, the drive band beingterminated adjacent the opposite ends of said chamber and the free endsthereof being connected by a link which avoids the chamber whilstmaintaining a reciprocating drive connection between said ends.

11. Apparatus according to claim 1 further comprising means fortransporting footwear into and from the chamber comprising a slide inthe trackway at a location preceding the intake end of the chamber;carrierengaging catch means on the slide; and drive means for movingsaid slide into the chamber at required times through the open intakeend thereof, the arrangement being such that, at this time, said catchmeans draw fresh carriers into the chamber and simultaneously ejecttherefrom carriers previously in the chamber the slide subsequentlybeing withdrawn to leave said fresh carriers in the chamber.

12. Apparatus according to claim 1, wherein a heat setting chamber isprovided in the conveyor system at a location immediately preceding thefirst-mentioned chamber, whereby footwear carried by said carriers canbe subjected to a heat setting operation prior to entering said chamber.

1. Footwear treating apparatus comprising a conveyor system including atrackway; a plurality of carriers in said trackway; lasts on saidcarriers for carrying partly-finished shoes for treatment; drive meansfor intermittently driving the carriers around the trackway; a vacuumchamber through which the trackway passes; means for sealing saidchamber in a pressure-tight manner to enclose a group of last-mountedshoes for treatment; means for heating the shoes and lasts; andpressure-reducing means for subjecting the shoes within the chamber tosub-atmospheric pressure to cause accelerated evaporation of liquidtherefrom.
 2. Apparatus according to claim 1 wherein said means forheating the shoes and lasts comprises induction heating means forheating the shoes and lasts while the shoes and lasts are atsub-atmospheric pressure.
 3. Apparatus according to claim 1 wherein saidheating means comprises pre-heating means for heating the shoes andlasts before entry into said vacuum chamber.
 4. A method of treatingfootwear comprising mounting partly-finished shoes for treatment onlasts on carriers, conveying the carriers intermittently along atrackway and through a vacuum chamber, sealing said chamber to enclose agroup of last-mounted partly-finished shoes for treatment, heating theshoes and lasts, and subjecting the shoes within the chamber tosub-atmospheric pressure to cause accelerated evaporation of liquidtherefrom.
 5. A method of treating footwear comprising mountingpartly-finished shoes for treatment on lasts on carriers, conveying thecarriers intermittently along a trackway and through a vacuum chamber,heating the shoes and lasts prior to the entry thereof into saidchamber, sealing said chamber to enclose a group of last-mountedpartly-finished shoes for treatment, and subjecting the shoes within thechamber to sub-atmospheric pressure to cause accelerated evaporation ofthe liquid therefrom.
 6. Apparatus according to claim 1, wherein thechamber is open-ended and doors operable by pneumatic cylinder and ramdevices are provided to close the ends of the chamber in pressure-tightfashion at required times.
 7. Apparatus according to claim 1, whereinthe pressure reducing means comprise a vacuum pump including waterextraction means, and wherein a pneumatically-operated valve is mountedin the wall of the chamber to connect the pump to the chamber atrequired times.
 8. Apparatus according to claim 7, comprising a furtherpneumatically-operated valve mounted in the wall of the chamber andarranged to connect the interior of the latter to atmosphere at requiredtimes.
 9. Apparatus according to claim 1, further comprising a waterspray device connected to the chamber and arranged to spray water ontoarticles of footwear therein at required times, this device comprising apiston and cylinder unit arranged to be supplied with water; a spraynozzle in the wall of the chamber to which the cylinder of said unit isconnected; and a pneumatically-operated piston and cylinder unit oflarger diameter than said water cylinder, wherein the pistons of the twounits are connected so that movement of the pneumatic piston in onedirection causes water to be drawn into the water cylinder, and movementin the other direction causes the water in said cylinder to be deliveredto the spray nozzle.
 10. Apparatus according to claim 1, wherein thecarrier drive means include a reciprocating saw-tooth drive band in thetrackway, and wherein each carrier has a pivoted catch device on itsunderside for engagement by said band, the arrangement being such thatthe teeth on the drive band engage the catch devices in one direction ofband reciprocation and drive the carriers, but pass idly across saiddevices in the other direction of strip reciprocation, the drive bandbeing terminated adjacent the opposite ends of said chamber and the freeends thereof being connected by a link which avoids the chamber whilstmaintaining a reciprocating drive connection between said ends. 11.Apparatus according to claim 1 further comprising means for transportingfootwear into and from the chamber comprising a slide in the trackway ata location preceding the intake end of the chamber; carrier-engagingcatch means on the slide; and drive means for moving said slide into thechamber at required times through the open intake end thereof, thearrangement being such that, at this time, said catch means draw freshcarriers into the chamber and simultaneously eject therefrom carrierspreviously in the chamber the slide subsequently being withdrawn toleave said fresh carriers in the chamber.
 12. Apparatus according toclaim 1, wherein a heat setting chamber is provided in the conveyorsystem at a location immediately preceding the first-mentioned chamber,whereby footwear carried by said carriers can be subjected to a heatsetting operation prior to entering said chamber.